RE: any insulation recomendations for magnet wire

[Terry Fritz <twftesla-at-uswest-dot-net>]

Hi,

	I would also note that secondary flashovers and arcs seem to run as big
single arc along the 'surface' of the coil instead of a bunch of little
arcs between each of the turns.

Cheers,

	Terry



At 01:12 PM 7/18/00 +1200, you wrote:
>Hi John,
>         I'm not sure that V/turn is a particularly useful 
>concept when it comes to rating resonator insulation. An 
>example: I can test a certain gauge of wire (with a 
>correspondingly thick coating of polyesterimide or whatever) 
>to 6kV without it breaking down between two adjacent pieces of 
>the same wire. More actually - I'm being conservative. So, 
>let's say we have a coil actually doing 6kV/turn and 
>furthermore that coil has the "standard" 1000 turns. I can 
>wind something like that with a height of less than a metre. 
>But can I get output to hit the insulation limit of my wire? 
>Not a show in hell - we're talking about 6MV over a distance 
>of less than 1m. Cannot be done without winding flashovers. 
>Generally one finds that the tracking distance required to 
>prevent a flashover does not adhere linearly to the total 
>voltage.
>      I bet there are very few if any coils which even come 
>close to taxing the turn-turn wire insulation. I think your 
>program should instead be looking at total voltage/total 
>secondary length.
>
>Regards,
>Malcolm
> 
>
>On 17 Jul 00, at 18:25, Tesla list wrote:
>
>> Original poster: "John H. Couture" <couturejh-at-worldnet.att-dot-net> 
>> 
>> 
>> Ed, David -
>> 
>> As you know I am interested in the design of Tesla coils and improving my
>> JHCTES Ver 2.3 TC computer program. Therefore, when somone mentions TC
>> design my interest is aroused because I may learn something new. Tesla
>> coilers have always had the problem of the secondary wire insulation
>> breaking down during coil operation. As you said this could be due to faulty
>> design. However, it could also be due to a well designed coil except for not
>> enough secondary wire insulation. How would the designer know this without
>> information regarding the voltage stress on the secondary wiring?
>> 
>> When I was developing the JHCTES program I realized a parameter that would
>> alert the designer to the secondary wire voltage stress would be of use in
>> the selection of the wire insulation. The parameter I choose was a "volts
>> per turn" which varies with every coil. It is obvious this parameter is
>> approximate but does give the designer guidelines with which to select the
>> secondary wire insulation.
>> 
>> Ever coiler who has done much coiling has at one time had problems with
>> secondary wire insulation breakdowns during operation. These breakdowns can
>> occur anywhere along the secondary coil. The voltage to ground varies
>> nonuniformly from the bottom to the top terminal of the coil. However, the
>> volts per turn would vary very little so an approximate average volts per
>> turn can be used. At present the estimated volts per turn can be found only
>> in the JHCTES Ver 2.3 program.
>> 
>> John Couture
>> 
>snip...